1. Field of the Invention
The present invention relates to an automatic speed changing apparatus preferably employable for a motorcar. The present invention may be applied to an automatic speed changing apparatus which is usable for many kinds of mechanisms for transmitting a rotational force.
2. Description of the Prior Art
As is well known, two types of speed changing apparatuses have been heretofore used for motorcars, one of them being a manual type speed changing apparatus and the other one being an automatic speed changing apparatus. With the conventional manual type speed changing apparatus, there is a need of disengaging a clutch from an engaged state at every time when a gear position is shifted to another one to adapt to the current running state of a motorcar. To this end, time and labor are required to disconnect the clutch from an engaged state and bring it in the engaged state and vice versa. In addition, to compensate the reduction of speed when gears are shifted to other positions, an acceleration pedal should be depressed by a driver to increase the number of revolutions of an engine just before the clutch is disengaged from the engaged state and when it is brought in the engaged state again. This causes fuel to be consumed uselessly. Further, to increase the running speed from a lower level to a higher level, the clutch, should be repeatedly disengaged from the engaged state and brought in the engaged state, resulting in the motorcar failing to be accelerated smoothly. Another problem inherent to the conventional speed changing apparatus is that energy is consumed uselessly because power transmission is achieved in the presence of friction between adjacent clutch plates with some slippage occuring therebetween while the clutch is disengaged from the engaged state and then brought in the engaged state.
On the other hand, with respect to the conventional automatic speed changing apparatus it has been pointed out as problems that it is complicated in structure, it requires many structural components, it can not be easily repaired when some trouble takes place with it, it is designed and constructed in larger dimensions as a whole and moreover it requires a wide space for mounting it on a motorcar.